Currently, mass transportation carriers are widely used in our modern society. Mass transportation carriers, such as trains and buses, are particularly useful in crowded urban areas where traffic congestion is a problem. Typically, trains and buses employ several light sources for the safety and convenience of its passengers. Among the possible choices of light sources, the fluorescent light tube is generally preferred over the incandescent bulb due mainly to its economics of operation and the reduced heat generated by the fluorescent tube.
With the advent of automatic vehicle location (AVL) systems, such as the "Loran-C" system, many mass transportation vehicles have been equipped with AVL devices so that a provider of a mass transportation service can determine the location of its vehicles. However, when an AVL device is installed in a vehicle employing fluorescent lights, the AVL device may be rendered inoperative due to the radio frequency (RF) interference radiated by the fluorescent lights and associated wiring.
One approach to reduce the RF interference from the fluorescent lights included the installation of a grounded wire grid that surrounded the fluorescent tube. However, this screening technique is expensive to implement, reduces the light output from the fluorescent tube and renders the normally easy task of replacing an inoperative tube a tedious and laborious process. Accordingly, a need exists to develop a means for suppressing the radio frequency interference generated by the fluorescent lights so that mass transportation vehicles may be equipped with the benefit of the AVL devices, while maintaining proper lighting for the safety and convenience of the passengers.